1. Technical Field of the Invention
Multiplex grouping device for grouping sequentially fed articles, comprising at least one loading station with a feed sensor, at least one unloading station with a discharge sensor and at least two conveying means, the conveying means comprising a plurality of mechanically interconnected carriers, and each conveying means being movable by a respective controllable drive, which can be activated by a central controller via a respective speed regulator and articles can be transferred onto the carriers from each loading station and articles can be transferred from the carriers into each unloading station
2. Description of the Prior Art
In the state of the art, a plurality of interconnected machines with in some cases complex movement sequences, such as packaging machines, can often only process the received articles at maximum speed if the articles are supplied at uniform spacings from one another or in groups with a particular spacing pattern.
Therefore such complex machines are arranged in so-called grouping stations, which adjust the required spacing or the required spacing pattern. The most widely used process is the series connection of a plurality of conveyor belts. The first belt acts as an accumulating belt by reducing its speed with respect to the incoming stream of articles such that all articles on the conveyor belt collide with one another, during which they are prevented from escaping at the sides by means of side-delimiting wall. On at least one connecting belt with high speed, the articles are drawn apart again, and are then all at the same spacing from one another.
During the transition from one belt to the next, the article temporarily comes into contact with both adjacent belts. However, since their velocity is different, the article slides on at least one of the belts. So that it is not damaged in this phase, the friction between the article and the belt must not be too high. On the other hand, the friction must not be so low that the article is no longer sufficiently accelerated and slowed by the belt. This results in the disadvantage that not every article can be combined with any arbitrary belt material.
Another restriction is that, depending on the geometry of the goods, which, because of the transition from one belt to the next cannot be sufficiently large, another belt must be interposed. The use of up to eleven so-called correction belts is known.
Another problem of this principle is that, where there is a relatively large gap in the stream of incoming articles, the braking effect of the accumulating belt is not sufficient to close the large gap, whereupon, during discharge of the articles, too, a spacing occurs that is greater than the actually required value.
Then the following machine executes a so-called idle stroke, e.g. a machine that packages articles in so-called “sausage bags,” cuts an empty plastic section and forms it into a sausage bag, but without it containing any goods. If the next station is a shrink oven, in which the film is shrink by heating to the extent that it bears against the articles, a bag may completely melt down without the cooling of the goods contained in the bag, and be heated so intensively that it catches fire.
In this application example, an empty cycle has the effect that the entire production line must be stopped, the melted bag removed and the system started up again, which serious affects the average processing rate.
Other disadvantages of the prior art are the limited flexibility due to the geometrical conditions. The correction belts should be chosen in their dimensions such that they harmonize with the corresponding product sizes, for which purpose a multiplicity of belts must be interconnected for relatively large products. The space requirement is always high, since the belts are arranged in series and the length of each belt must be matched to the dimension of the smallest and largest product.
Other restrictions are that the correction belts must be matched to the characteristics of the following machines, if their velocity can only be changed within a very low percentage of the nominal value.